In a manufacturing process of electronic devices such as a semiconductor device and a liquid crystal display device, for example, an etching process for etching a film on a substrate in a desired pattern is performed to form a predetermined circuit pattern on the substrate. A plasma processing apparatus has been widely used for the etching process. The plasma processing apparatus includes in a processing chamber thereof a lower electrode for mounting thereon the substrate and an upper electrode serves as a showerhead for injecting a predetermined gas toward the substrate on the lower electrode. In the etching process, a radio frequency power is applied between the upper and the lower electrode under the condition that a predetermined gaseous mixture is injected through the showerhead into the processing chamber to generate a plasma, thereby etching a film on the substrate.
Here, in case of etching the substrate in the processing chamber by generating a plasma therein, etching characteristics such as an etching rate and an etching selectivity at a central portion of the substrate is different from those at a peripheral portion thereof. One of the reasons for this is considered that a density of the plasma generated in the processing chamber is not uniform when the density in the central portion is compared with that in the peripheral portion. Accordingly, there has been proposed in, e.g., Japanese Patent Laid-open Publication Nos. H9-45624 and 2002-184764 that a so-called focus ring is disposed around the substrate mounted on the lower electrode to enlarge the plasma generation range up to the surrounding area of the substrate, thereby making the plasma density even above the substrate and resulting in a uniform etching processing.
However, the focus ring and other components disposed in the processing chamber of the plasma processing apparatus are provided with their identification indicia for management thereof. The management using the identification indicia makes it possible to determine a component replacement timing or trace, e.g., a manufacturing process of a defective component. Conventionally, in case of marking an identification indicia on a component of the plasma processing apparatus, the identification indicia such as numbers and/or characters is formed on the surface of the component in a way that continuous recesses are inscribed therein by using a so-called laser marking method.
However, since the components disposed in the processing chamber of the plasma processing apparatus are exposed to a high temperature ambience during the processing, the components having the identification indicia as described above are likely to develop an crack at the identification indicia due to a thermal stress applied thereto during the plasma processing. Particularly, a component formed of Si such as the focus ring and other components formed of a brittle material such as quartz, alumina ceramic, yttria ceramic and SiC are likely to develop a crack at the identification indicia.